Manufacture of hydraulic cement products



m; 17, 1M7. G.,L. EASTERBERG ETAL 2,422,345

NUFACTURE 0F HYDRAULIC CEMENT PRODUCTS Filed Aug. 2, 1940 'IIIIIIIII INVENTORS 'usrnv: L. Enarcnazne Run? A. NACARTHUR Patented June 17, 1947 MANUFACTURE OF HYDRAULIC CEMENT PRODUCTS Gustave L. Easterberg, Pleasant Ridge, and Roger A. MacArthur, Wyoming, Ohio, assignors to The Philip Carey Manufacturing Company, a

corporation of Ohio Application August 2, 1940, Serial No. 349,636 2 Claims. ('01. 92-39) This invention relates to hydraulic cement products, and particularly relates to cement-asbestos products, such as shingles, sidings, and corrugated and flat lumber, comprising mixtures of Portland cement and asbestos fibers, with or without the addition of other fibers and fillers.

Most of the cement-asbestos products of commerce are made on wet machines, which are modifications of the types used for making paper, such as the Fourdrinier and cylinder machine. These machines form a water-laid paste of Portland cement and asbestos fibers and wrap it on an accumulator roll, said paste having been partially dewatered on a felt or cylinder or both. The accumulated sheets are cut from the accumulator roll when the thickness thereof is sufiicient. In the usual practice of the art, the sheets must be accumulated for an average of about one minute. The process is an intermittent one, and the sheets produced thereby are handled in units. The formed sheets are ordinarily wet-trimmed to the approximate size of the shapes made therefrom, and are pressed in platen presses to compact them. The handling of these sheets is expensive, but even more expensive is the time taken to wrap a sheet on the accumulator roll.

The Norton process of fabricating cement-asbestos sheets is, on the other hand, a continuous process, and the rate of production far exceeds that of the wet machine process. In the practice of this process, a dry or slightly moistened mixture of Portland cement and asbestos fiber is placed on a travelling endless belt by suitable means and in the full required thickness, and is dampened with water sprays and is lightly rolled for compaction, following which the sheet is pressed, indurated and cut to size.

The sheet of the Norton process is economical, being made in full. thickness continuously, but suffers a serious drawback, in that the asbestos fibers are not properly oriented to give the maximum reinforcement to the sheet structure. The wet machine processes largely orient the asbestos fiber in the direction of travel of the felt, and the sheets made thereon, when cured, or indurated, are strong and not brittle. In the practice of the Norton process, it is necessary to add a greater proportion of more expensive asbestos fiber to achieve reasonable strength and, regardless of the amount of fiber added within reason, the cured product is excessively brittle. Excessive brittleness can not be tolerated in cement-asbestos products because of resultant unavoidable damage to the product in handling, application and service.

We have found that both transverse strength and brittleness of cement-asbestos products are largely determined by the characteristics of the surfaces of saidproducts. A cement-asbestos shingle, for example, made by the Norton process is very brittle as compared with a similar unit made on a wet machine. We have found that a shingle can be made with wet-laid surf-ace portions having the fibers therein oriented or lying parallel to the surface and with the interior portion of the shingle oriented or not is not brittle. The invention relates to cement-asbestos or other hydraulic cement sheets, having linear fibers therein, with the fibers in one portion oriented. The fibers in the other portions of the sheet may or may not be oriented.

For a better understanding of the invention, reference may be made to the accompanying drawings, in which:

Fig. 1 is a schematic view of a portion of a machine embodying the invention; and

Fig. 2 is a schematic view of a modified form.

Conveyor l is a felt capable of absorbing water and travels continuously over the rolls 2, 3, 4, 5 and 6 in the direction indicated by the arrow.

The box l, with a gate 8 is kept supplied with a with a means for introducing the required thickness of said dry or slightly moistened mixture layer l2 on the partially dewatered slurry from box I. A rake, bar or brush it levels the overlay E2 of cement-asbestos and the water spray it molstens it so that when compacted under the roll 55, the composite sheet I6 is thoroughly dampened throughout its thickness, part of the water com-" ing from the spray M, and part from the wet laid layer II. The moisture content is made more uniform through the sheet by being introduced both above and below the dry or slightly moist overlay mixture. The compacted composite sheet is thus sufiiciently increased and reenforced in strength by reason of the wet-laid sheet it so layer 1 1.

process in which no part is wet laid and the fibers therein are not oriented longitudinally of the surface. A flying knife It may be used to cut the compacted sheet 16 if desired. The cleaning water for the felt 16, the whipper I9 and the drying box 20 are standard in the art and are shown merely as illustrative.

In another modification of this novel process, a wet-laid sheet is placed on the other surface of the sheet 16 opposite to layer It, as shown in Fig. 2. In this modification, an additional wet laid sheet 21 is made on a felt 22 and is picked ofl the felt at the point 23 by the compacting roll l and superposed on sheet 16 opposite to This sheet is dewatered by the suction box or boxes 25. The pressure of the roll lagainst the material fed over roll 4 on the felt conveyor functions to combine the sheet 21 with the combination sheet '16. This sheet 2i is made similar tothe wet-laid sheet H of Fig. 1 and is applied to E2 opposite to layer ii. The composite sheet 26 of Fig. 2 possesses the predominating characteristics of a wet-laid sheet and may be handled as such, and is particularly adapted to roll-pressing as disclosed in our above mentioned copending application.

We have found that the indurated product of Fig. 2 has substantially the same physical properties and. freedom from brittleness as a sheet made by a wet machine, and as stated above is cheaper to produce as a result of being made continuously.

While th modifications cf Figs. 1 and 2 are given as illustrative, minor changes may he made without departing from the spirit of this inven tion, For example, a cylinder machine may be used instead of the Fourdrinier machine shown in Figs. 1 and 2 to make one or both of the sheets ii and 21, or a suitable high capacity suction filter such as an Oliver filter may be used to form thicker sheets.

We claim:

1. A continuous method of making hydraulic cement products comprising forming a plurality of water-laid sheets of hydraulic cement, having linear fibers therein which are oriented longitudinally of the surface of said sheets, interposing a non-water laid hyclTaulie cement-asbestos layintegrate the juxtaposed sheets by continuously feeding the juxtaposed structure between press rolls.

2. A continuous method of making hydraulic cement products comprising forming a plurality of water-laid sheets of hydraulic cement, having linear fibers therein which are oriented longitudinally of the surface of said sheets, interposing a non-water-laid hydraulic cement layer between the wet waterelaid sheets, and compressing the juxtaposed structure against an absorbent resilient support to remove the water and integrate the juxtaposed sheets by continuously feelcling the juxtaposed structure between press re! s.

- GUSTAVE L. EASTERBERG.

ROGER A. MACAR'I'HUR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,039,266 Dieffenbach Sept. 24, 1912 1,544,843 Ledeboer e July 7, 1925 2,184,619 Leonard Dec. 26, 1939 Re. 12,594 Hatschek Jan. 15, 1907 1,819,840 Holcomb Aug. 18, 1931 1,799,350 Barnes Apr. 7, 1931 1,039,413 Klee Sept. 24, 1912 940,449 Ferla Nov. 16, 1909 1,140,601 Lappen May 25, 1915 1,143,931 Babcock June 22, 1915 1,463,961 Ledeboer Aug. 7, 1923 1,687,681 Mattison Oct. 16, 1928' 1,804,560 Hussey May 12, 1931 1,829,137 Piessevaux Oct. 27, 1931 1,880,692 Berry 1 Oct, 4, 1932 2,013,332 Sale Oct. 22, 1935 2,177,543 Ferla Oct. 31, 1939 FOREIGN PATENTS" Number Country Date 678,640 France Apr. 2, 1930 

